<template>
  <div class="flow-container">
    <div class="containers" ref="content">
      <div class="canvas" ref="canvas"></div>
      <div id="js-properties-panel" class="panel"></div>
      <ul class="buttons">
        <li>下载</li>
        <li>
          <a ref="saveDiagram" href="javascript:" title="download BPMN diagram">BPMN diagram</a>
        </li>
        <li>
          <a ref="saveSvg" href="javascript:" title="download as SVG image">SVG image</a>
        </li>
      </ul>
    </div>
  </div>
</template>


<script>
  // 引入相关的依赖
  import BpmnViewer from 'bpmn-js'
  import BpmnModeler from 'bpmn-js/lib/Modeler'
  import propertiesPanelModule from 'bpmn-js-properties-panel'
  import propertiesProviderModule from 'bpmn-js-properties-panel/lib/provider/camunda'
  import camundaModdleDescriptor from 'camunda-bpmn-moddle/resources/camunda'
  import customTranslateModule from '@/components/bpmn-config/customTranslate'//汉化
  export default {
    name: 'flow_bpmn',
    data(){
      return {
        // bpmn建模器
        bpmnModeler: null,
        container: null,
        canvas: null,
        xmlStr: null,
        processName: ''
      }
    },
    watch: {

    },
    methods:{
      createNewDiagram() {
        const bpmnXmlStr = '<?xml version="1.0" encoding="UTF-8"?>\n' +
          '<bpmn:definitions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" id="Definitions_0fppxr8" targetNamespace="http://bpmn.io/schema/bpmn">\n' +
          '  <bpmn:process id="Process_1" isExecutable="false">\n' +
          '    <bpmn:startEvent id="StartEvent_1" name="开始">\n' +
          '      <bpmn:outgoing>SequenceFlow_0nrfbee</bpmn:outgoing>\n' +
          '    </bpmn:startEvent>\n' +
          '    <bpmn:task id="Task_0ho18x0" name="结束">\n' +
          '      <bpmn:incoming>SequenceFlow_0nrfbee</bpmn:incoming>\n' +
          '      <bpmn:outgoing>SequenceFlow_00ho26x</bpmn:outgoing>\n' +
          '    </bpmn:task>\n' +
          '    <bpmn:sequenceFlow id="SequenceFlow_0nrfbee" sourceRef="StartEvent_1" targetRef="Task_0ho18x0" />\n' +
          '    <bpmn:sequenceFlow id="SequenceFlow_00ho26x" sourceRef="Task_0ho18x0" targetRef="Task_1ymuvem" />\n' +
          '    <bpmn:sequenceFlow id="SequenceFlow_18df8vb" sourceRef="Task_1ymuvem" targetRef="EndEvent_1c0ed2n" />\n' +
          '  </bpmn:process>\n' +
          '  <bpmndi:BPMNDiagram id="BPMNDiagram_1">\n' +
          '    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">\n' +
          '      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">\n' +
          '        <dc:Bounds x="173" y="102" width="36" height="36" />\n' +
          '        <bpmndi:BPMNLabel>\n' +
          '          <dc:Bounds x="178" y="145" width="27" height="27" />\n' +
          '        </bpmndi:BPMNLabel>\n' +
          '      </bpmndi:BPMNShape>\n' +
          '      <bpmndi:BPMNShape id="Task_0ho18x0_di" bpmnElement="Task_0ho18x0">\n' +
          '        <dc:Bounds x="485" y="244" width="100" height="80" />\n' +
          '      </bpmndi:BPMNShape>\n' +
          '      <bpmndi:BPMNShape id="Task_1ymuvem_di" bpmnElement="Task_1ymuvem">\n' +
          '        <dc:Bounds x="712" y="391" width="100" height="80" />\n' +
          '      </bpmndi:BPMNShape>\n' +
          '      <bpmndi:BPMNShape id="EndEvent_1c0ed2n_di" bpmnElement="EndEvent_1c0ed2n">\n' +
          '        <dc:Bounds x="1056" y="568" width="36" height="36" />\n' +
          '        <bpmndi:BPMNLabel>\n' +
          '          <dc:Bounds x="1065" y="611" width="19" height="14" />\n' +
          '        </bpmndi:BPMNLabel>\n' +
          '      </bpmndi:BPMNShape>\n' +
          '      <bpmndi:BPMNEdge id="SequenceFlow_0nrfbee_di" bpmnElement="SequenceFlow_0nrfbee">\n' +
          '        <di:waypoint x="209" y="120" />\n' +
          '        <di:waypoint x="347" y="120" />\n' +
          '        <di:waypoint x="347" y="284" />\n' +
          '        <di:waypoint x="485" y="284" />\n' +
          '      </bpmndi:BPMNEdge>\n' +
          '    </bpmndi:BPMNPlane>\n' +
          '  </bpmndi:BPMNDiagram>\n' +
          '</bpmn:definitions>\n'
        // 将字符串转换成图显示出来
        this.bpmnModeler.importXML(bpmnXmlStr, function (err) {
          if (err) {
            console.error(err);
          }
          else {
            // 这里还没用到这个，先注释掉吧
            // that.success()
          }
        })
      },
      // 下载为SVG格式,done是个函数，调用的时候传入的
      saveSVG (done) {
        // 把传入的done再传给bpmn原型的saveSVG函数调用
        this.bpmnModeler.saveSVG(done)
      },
      // 下载为SVG格式,done是个函数，调用的时候传入的
      saveDiagram (done) {
        // 把传入的done再传给bpmn原型的saveXML函数调用
        this.bpmnModeler.saveXML({ format: true }, function (err, xml) {
          done(err, xml)
        })
      },
      // 当图发生改变的时候会调用这个函数，这个data就是图的xml
      setEncoded (link, name, data) {
        // 把xml转换为URI，下载要用到的
        const encodedData = encodeURIComponent(data)
        // 获取到图的xml，保存就是把这个xml提交给后台
        this.xmlStr = data
        // 下载图的具体操作,改变a的属性，className令a标签可点击，href令能下载，download是下载的文件的名字
        if (data) {
          link.className = 'active'
          link.href = 'data:application/bpmn20-xml;charset=UTF-8,' + encodedData
          link.download = name
        }
      },
    },
    mounted () {
      // 获取到属性ref为“content”的dom节点
      this.container = this.$refs.content
      // 获取到属性ref为“canvas”的dom节点
      const canvas = this.$refs.canvas

      // 建模，官方文档这里讲的很详细
      this.bpmnModeler = new BpmnModeler({
        container: canvas,
        //添加控制板
        propertiesPanel: {
          parent: '#js-properties-panel'
        },
        additionalModules: [
          // 左边工具栏以及节点
          propertiesProviderModule,
          // 右边的工具栏
          propertiesPanelModule,
          customTranslateModule
        ],
        moddleExtensions: {
          camunda: camundaModdleDescriptor
        }
      });

      // 下载画图
      let _this = this
      // 获取a标签dom节点
      const downloadLink = this.$refs.saveDiagram
      const downloadSvgLink = this.$refs.saveSvg
      // 给图绑定事件，当图有发生改变就会触发这个事件
      this.bpmnModeler.on('commandStack.changed', function () {
        _this.saveSVG(function (err, svg) {
          _this.setEncoded(downloadSvgLink, 'diagram.svg', err ? null : svg)
        })

        _this.saveDiagram(function (err, xml) {
          _this.setEncoded(downloadLink, 'diagram.bpmn', err ? null : xml)
        })
      })

      this.createNewDiagram(this.bpmnModeler);
    }
  }
</script>


<style lang="less">

  /*左边工具栏以及编辑节点的样式*/
  @import '~bpmn-js/dist/assets/diagram-js.css' ;
  @import '~bpmn-js/dist/assets/bpmn-font/css/bpmn.css';
  @import '~bpmn-js/dist/assets/bpmn-font/css/bpmn-codes.css';
  @import '~bpmn-js/dist/assets/bpmn-font/css/bpmn-embedded.css';
  .flow-container {
    display: flex;
  }
  /*右边工具栏样式*/
  @import '~bpmn-js-properties-panel/dist/assets/bpmn-js-properties-panel.css';
  .containers{
    position: absolute;
    background-color: #ffffff;
    width: 100%;
    height: 100%;
  }
  .canvas{
    width: 100%;
    height: 100%;
  }
  .panel{
    position: absolute;
    right: 0;
    top: 0;
    width: 300px;
    height:100%;
    overflow-y:scroll;
  }
  .buttons{
    position: absolute;
    left: 20px;
    bottom: 20px;
    &>li{
      display:inline-block;margin: 5px;
      &>a{
        color: #999;
        background: #eee;
        cursor: not-allowed;
        padding: 8px;
        border: 1px solid #ccc;
        &.active{
          color: #333;
          background: #fff;
          cursor: pointer;
        }
      }
    }
  }
</style>

